Considerable effort in recent years has been directed toward the synthesis of polynitrocubanes because of the potential use of this class of energetic materials as explosives, propellants, fuels and binders (Chemistry of Energetic Materials; Ed., G. A. Olah; D. R. Squire; Academic Press, Inc., San Diego, Calif., 1991. Also see Carbocyclic Cage Compounds; Ed., E. J. Osawa; O. Yonemitsu; VCH Publishers, Inc., New York, N.Y., 1992). The compact structures of cage molecules result in high densities, and the introduction of NO.sub.2 groups further enhances the density. The strain energy present in the cubane skeleton (&gt;166 kcal/mol) is an added bonus to its performance. Furthermore, preliminary results with polynitrocubanes indicate that such compounds are thermally very stable and are also very insensitive energetic materials. Consequently, it is of interest to introduce functional groups on the cubane skeleton which can be converted to intro group or other active functionalities.
Direct functionalization of nitrocubanes, while an attractive approach, has not heretofore been realized. Cationic or anionic reactions, due to the activity of the nitro groups give either decomposed products or recovered starting materials. We report here an efficient direct functionalization of a nitrocubane molecule by its irradiation in a solution of oxalyl halide (for a related case see Wiberg, K. B.; 10.sup.th Annual Working Group Meeting, Jun. 3-6, 1992, Kiamesha Lake, N.Y. For much simpler cases see Wiberg, K. B.; Williams, Jr., V. Z.; J. Org. Chem., 1970, 35, 369; Applequist, D. E.; Saski, T.; J. Org. Chem.; 1978, 43, 2399). This new and potentially powerful synthetic development will greatly shorten the number of steps necessary to obtain nitrocubane derivatives which are otherwise difficult to synthesize.